What makes these different than the ones pololu made, is that these got the hardware fix needed already done. This is needed for them to be drop-in replacements for the previous A4988/A4983 based drivers.

As you can see, another improvement is also the copper is extended from underneath the chip and out where a heat-sink can be put on, instead of slapping it on top of the chip, where the chip is not designed to be cooled from.

A little problem with the heat-sinks provided though… They are a bit too big.